Some implantable medical devices, such as pacemakers, defibrillators, and cardioverters (collectively referred to as implantable cardiac stimulation devices) are designed to monitor and stimulate the cardiac tissue of patients who suffer from cardiac arrhythmias. Using leads connected to the patient's heart, a cardiac stimulation device typically stimulates cardiac tissue by delivering electrical pulses in response to measured cardiac events which are indicative of a cardiac arrhythmia. Properly administered therapeutic electrical pulses often successfully reestablish or maintain the heart's normal rhythm, commonly referred to as normal sinus rhythm (NSR).
Implantable cardiac stimulation devices can treat a wide range of cardiac arrhythmias by using a series of adjustable parameters to alter the energy content, shape, location, and frequency of the therapeutic pulses. As such, these devices are now in widespread use and have become increasingly sophisticated over time. However, with the increased sophistication of the devices, the possibility of the devices experiencing difficulty following implantation has increased. It is very desirable that medical practitioners who are overseeing patients with implanted devices be kept advised of the problems experienced with other implanted devices so that the medical practitioners can take protective action with their own patients, if necessary. Generally, medical practitioners review device and heart performance data stored in a memory within the implanted device via a telemetry circuit that is part of the implanted device and an external programmer. While this provides the medical practitioner the ability to assess device performance, the practitioner must be able to determine if the implanted device includes components that have had problems in other implanted devices.
If and when a systematic problem is identified in a given model device, the manufacturers will notify the medical community via a letter describing the potential problems identified in a specific model device with recommendations as to patient management with respect to that potential system behavior. These safety alert bulletins advise medical practitioners of a possible problem based on observations from other implanted stimulating devices of the same model. An example of a safety alert information is a warning from a manufacturer indicating that a particular lead is suspect or that a type of pulse generator is prone to a specific unexpected behavior including but not limited to sudden no-output performance.
This type of information may provide an explanation to the medical practitioner for an observed performance characteristic of one of their patient's implanted devices or may even induce the medical practitioner to institute corrective actions even up to performing surgery to replace a suspect device. Moreover, the safety alert information may also provide recommended parameter ranges that the medical practitioner can use to set performance parameters of the implanted device using the programmers.
However, in practice, even if a medical practitioner reads the safety alert information sent by the device manufacturer, the medical practitioner may not recollect receiving the safety alert when examining a patient with an implantable device some months or even years later. In addition, the specific medical practitioner may never have received notification having not been registered as the medical practitioner following a patient with a suspect device when that patient enters the medical practitioner's practice at a later date. As a consequence, the medical practitioner may not always take the necessary corrective action.
Although implantable devices have been developed to perform some self-diagnostics, there currently does not exist a way to automatically cross-correlate safety alert information to medical data which is maintained on the implantable medical device.
In fact, the current generation implanted stimulation devices are not well adapted to even receive the information. For example, the more sophisticated implantable medical devices may include a small general storage memory that a medical practitioner may use to enter and store patient information. However, while a provider of the implantable medical device may recommend various types of information be included in this memory, it is the medical practitioner who ultimately decides what data is to be included in the memory. Typical patient information that is stored in the general storage memory include: a patient name, date of implant, model and serial numbers of atrial and ventricular leads, date of implant of atrial and ventricular leads if different from the pacemaker, diagnoses, and name of a monitoring medical practitioner. However, the medical practitioner may not necessarily store the aforementioned information in any particular order. Therefore, a computerized analysis of the data in an implanted device to assess if the device or devices have been included in a safety alert or other specific warning from the manufacturer is problematic since a computer system does not know the type and memory location of information contained in the general storage memory and whether the information is, in fact, even present.
Hence, while the current generation implantable stimulation devices include memories that are adapted to store information downloaded by a medical practitioner that can be subsequently recalled, the memories are not generally formatted in a manner that will allow for an automatic safety alert assessment. In particular, there are no existing protocols for storing the safety alert data in the device memory. Moreover, the memories are generally not adapted to display safety alert information to medical practitioners who are subsequently reviewing the device performance via an external programmer. Consequently, medical practitioners may not be able to recall all of the safety alert information for a particular implanted device. This may result in the medical practitioner overlooking a particular problem or misinterpreting data and setting device parameters incorrectly.
Therefore, there is a need for an implantable medical device which is capable of correlating safety alert, special warning and advisory information from the manufacturer for the model devices that comprise the implanted system including the electronic device and one or more peripheral components such as the leads. To this end, there is a need for a system which can receive safety alert information and compare this information to information about a patient's implanted cardiac device so that the communicating device or programmer can provide an appropriate warning to an evaluating medical practitioner following interfacing with the implanted device.